diff --git a/ChangeLog.d/default-curves.txt b/ChangeLog.d/default-curves.txt
new file mode 100644
index 0000000..1a80562
--- /dev/null
+++ b/ChangeLog.d/default-curves.txt
@@ -0,0 +1,8 @@
+Default behavior changes
+   * Some default policies for X.509 certificate verification and TLS have
+     changed: curves and hashes weaker than 255 bits are no longer accepted
+     by default.
+
+Removals
+   * Remove the compile-time option
+     MBEDTLS_TLS_DEFAULT_ALLOW_SHA1_IN_KEY_EXCHANGE.